BREAST CYTOPATHOLOGY

52 2. Non-neoplastic and Proliferative Lesions
• A small subset show molecular/chromosomal evidence of
a neoplastic nature. However, most lesions are thought to
be related to infectious etiology.
• Immunoexpression of the ALK protein as a result of
chromosomal translocation involving 2p23 is seen in a
number of cases.
Cytomorphologic Characteristics
• A proliferative process of myofibroblasts
• Sparsely cellular aspirates
• Characterized by benign cellular features with a
poly morphous population of mostly chronic inflammatory
cells, plus histiocytes and spindled fibroblasts (or
myofibroblasts)
• Benign-appearing ductal epithelium may be present, as
well as connective tissue fragments
• Some features may resemble fat necrosis
• Vascular-endothelial proliferation often noted
• Histiocytes and spindled cells may show well-formed
intranuclear inclusions
• No granulomas
Pitfalls and Differential Diagnosis
• Granulomatous mastitis
• Fat necrosis
• Granular cell tumor
• Fibromatosis
• Metaplastic carcinoma
• Myofibroblastoma
Primary Amyloid Tumor
Clinical Features
• Primary amyloid tumors are rare nonneoplastic lesions.
• Clinically and radiologically, the findings are often indeterminate,
necessitating FNA.